1. Technical Field
The present invention relates to a technology for checking for failures of electro-optical devices, such as liquid crystal display devices.
2. Related Art
In electro-optical devices that form images using electro-optical characteristics of liquid crystal or the like, a checking operation for determining whether or not a failure occurs is normally executed in the process of manufacturing in order to prevent a negative effect on post-processes. In particular, in active-matrix electro-optical devices, determination as to whether or not a failure occurs is important since an active element, such as a transistor for switching on and off a pixel, is formed on an element substrate. In addition, in electro-optical devices containing a peripheral circuit, such a checking operation is much more important since part or all of a drive circuit is formed, together with an active element for switching on and off a pixel, on an element substrate.
Thus, a technology for determining whether or not a failure occurs is suggested, for example, in JP-A-10-260391. The determination is performed by monitoring an output signal of a checking circuit prepared in advance in an electro-optical device.
However, for electro-optical devices based on a demultiplexer system called hybrid electro-optical devices, it is difficult to achieve a satisfactory checking operation due to the recent development of high-definition displays. More specifically, in a demultiplexer system in which data signals to be supplied to n data lines are input in a time-division manner and in which the n data lines are selected one by one in the time-division manner, a so-called X driver does not exist. Thus, for example, checking as to whether or not data lines adjacent to each other are short-circuited cannot be executed.